I'm not quite sure I get your point (or you get mine.) This was supposed to be a "thought experiment." Pickup trucks and other vehicles can be manufactured in greater quantities to meet demand. Other vehicles can be chosen: vans, cars, panel trucks.
On the other hand, women cannot be manufactured in greater numbers; nor are there any other available marriage partners for men. That leaves huge numbers of men permanently unmarriageable. This has consequences beyond the individual.
I suspect that's why polygamy is such a social-ecology throwback. It's hard for societies to assimilate the energies of large numbers of mateless men constructively. In our own society, men who never marry are vastly overrepresented in prison; in Islamic societies they make up the bulk of the criminals, crazies, cannon-fodder.
Can we talk about this?